Here's a topic guaranteed to start controversy. Which Linux distribution is best? It all depends on your criteria for judging. Even then the topic is highly subjective. Here are a few nominees for "best distro" in specific categories.

Ubuntu may be popular, but it's certainly NOT a best one out there in terms of usability, ease of use, available software, openness [in terms of freedom - libre].

I can't think of an easier to use DE than Unity out there. From a kid to an old person, from a newbie to a pro, it couldn't be more obvious. Usability and ease of use are the two most prominent qualities of Ubuntu according to any review out there.

Software availability is second to none. Almost every app that exists for Linux will be released for Ubuntu (due, precisely, to its popularity), be it open or closed.

It's as open as you want it to be. If you are one of those who gets urticaria when exposed to closed source software, you can use Trisquel, which is the libre-only version of Ubuntu (and was created at my home town's University of Vigo, Spain, by the way). I happily use closed source software, but you can't say there's not an option.

You don't have to like Ubuntu, but these points of yours are rather weak.